The present invention relates to an inertial counterbalance for an antenna.
The present art radar antenna and the like tend to be constructed with a very high mass which must be conveniently rotated in the elevation direction between zenith and horizontal stations. The structures may be quite heavy, on the order of several thousand pounds and it has been found quite difficult to move these antennas with reliability and safety.
In recognition of this problem several attempts have been made at counterbalancing the inertia of the antenna to simplify the dynamic motion problems. These attempts have generated some undesirable results. Counterbalancing means usually include counterweights which have structurally interferred with the pedestal structures of the antenna. Such interference prevents desired full hemispherical sky clearance and limits the effectiveness of the antenna.
In U.S. Pat. No. 3,233,475, to Barber, the counterbalancing means comprises a series of gears disposed directly beneath the pivotal axis of the antenna structure. U.S. Pat. No. 3,375,523 illustrates another attempt to counterbalance the antenna.
The devices illustrated in the above patents and several others known in the art are somewhat effective in reducing the inertia of the antenna and to some degree simplify the response necessary of the drive motor means. However, all the prior art devices, in one way or another, do not completely solve the problem that the present invention is directed toward. The instant invention acts as a counterweight when the antenna is rotated from its zenith position toward its horizontal position and decreases the possibility that the antenna will inadvertantly fall too fast thereby damaging its critical components. The counterbalance also acts to store energy during the descent of the antenna structure, which energy is available to assist in its ascent toward its zenith point.